Current transfer in connection with electric welding

ABSTRACT

In electric welding utilizing a wire to supply metal to a weld area a current is supplied to the wire as the wire is continuously advanced to the weld area. In accordance with the invention the current can be effectively supplied to the wire utilizing a plurality of electrically conductive rollers having surfaces which engage the wire. These rollers roll in synchronism with the wire and transfer current supplied to them to the wire.

D United States Patent 1191 1111 3,789,186 Rygiol Jan. 29, 1974 CURRENTTRANSFER IN CONNECTION 3,406,888 l0/l968 Ramey 226/187 WITH ELECTRICWELDING 3,447,730 6/1969 Jeanette 226/184 X 3,672,655 6/1972 Carter226/184 X Inventor: Henry yg 16437 Jamne, 3,675,837 7/1972 Gerould226/187 Whittier, Calif. 90603 Primary Examiner-J. V. Truhe 1 7 [22]Flled Mar 13 9 2 Assistant Examiner-Hugh D. Jaeger [21] Appl. No.:233,961 Attorney, Agent, 0r'FirmEdward D. OBrian 521 U.S. c1 219/130,226/184 [57] [51] Int. Cl 323k 9/00 In electric Weldmg utlhzmg a Wire topp y metal to a [53] Fidd f S h 219 130 13 74; 22 4 weld area a currentis supplied to the wire as the wire 22 137 19 314 is continuouslyadvanced to the weld area, In accordance with the invention the currentcan be effectively [56] References Cit d supplied to the wire utilizinga plurality of electrically UNITED STATES PATENTS conductive rollershaving surfaces wh1ch engage the 2 475 346 7 1949 W wire. These rollersroll in synchronism with the wire 2820137 151958 i and transfer currentsupplied to them to the wire. 3,396,888 8/1968 Rygiol 226/190 X 5Claims, 4 Drawing Figures CURRENT TRANSFER IN CONNECTION WITH ELECTRICWELDING BACKGROUND OF THE INVENTION In certain types of electric welding21 weld is created utilizing a wire or wire-like member so that suchwire is advanced to the weld area where metal is deposited to create aweld as the result of current flow between the end of the wire and oneor more metal members in the weld area. Procedures of this type are wellknown and are commonly utilized. With this type of welding a variety ofdifferent devices may be utilized in feeding the wire through a weldarea or in advancing the wire to the weld area. One particularlysuitable device for such utilization is disclosed in the Rygiol US. Pat.No. 3,396,888.

Although the type of welding described in the preceding is wellestablished and although suitable wire feeders for use with this type ofwelding are known, it is considered that there remains a significantproblem with respect to the procedures followed in this type of weldingfor transferring an electric current to the wire adjacent to the weldarea. conventionally such current transfer is accomplished by passingthe wire through an electrically conductive contact tube adjacent to theweld area as the wire is advanced. This type of procedure is consideredto have significant limitations and disadvantages.

Although normally such a tube has an internal diameter corresponding tothat of the wire passed through it, not infrequently there have beenproblems in obtaining adequate electrical contact between such a wireand the interior of the tube. Current transfer is, of course, dependentupon such contact. Not always does a wire precisely fit within a tube sothat there will be adequate contact. This is considered to beparticularly the case when the tube becomes somewhat warm throughcontinued use.

In order to increase the contact between such a transfer tube and thewire so as to insure adequate electrical current transfer such tubeshave been bent. This is to insure electrical contact between a wire anda tube by the wire rubbing against the interior of the tube as it passesaround a corner or angle. This type of expedient is consideredundesirable. because in the areas of such contact the interior surfaceof the tube will tend to wear. Such wear obviously decreases theeffective life of a contact tube. Also, as such wear occurs the chancesof satisfactory electrical contact between the tube and a wire becomediminished.

With welding procedures utilizing both straight and bent currenttransfer or contact tubes as described briefly in the precedingdiscussion there is a significant chance of other problems than arespecifically indicated in this discussion. Included with such otherproblems is the danger of so-called current burn back and the dangerthat the wire within a tube will tend to clog up within the interior ofit.

With both of the types of contact tubes indicated there is also theproblem of internal friction within the contact tube making it difficultto advance the wire to a weld area. In general, the lower the frictionimpeding wire movement the easier it is to advance a wire withoutdifficulty. When there is little friction opposing wire movement theequipment used to advance the wire need not have the same wire movingcapacity as when a wire can be advanced under such conditions thatcomparatively little friction opposes wire movement.

As a result of these and various related factors it is considered thatthere is a significant need for improved current transfer to a wire orwire-like member in welding procedures in which such a wire iscontinuously advanced and moved to a weld area where metal is depositedso as to create a weld. It is also considered that this need has beenlong standing since welding procedures of the type indicated herein havebeen known and utilized for many years. In connection with this it isnoted that current contact or transfer tubes as discussed in thepreceding discussion, although utilitarian, have been specificallyidentified as needing improvement.

SUMMARY OF THE INVENTION A broad objective of the present invention isto provide new and improved current transfer for use in connection withelectric welding in order to satisfy or meet the need indicated in thepreceding discussion. From this it will be more or less implied thatanother broad objective of the present invention is to provide new andimproved current transfer in connection with electric welding of thetype indicated so as to overcome certain of the problems and limitationsof customary practice.

In its more specific aspects, the invention is concerned with a new andimproved method for use in supplying an electric current in a wire assuch a wire is advanced in welding as described and is concerned withnew and improved apparatuses for use in carrying out this method. Theinvention also is intended to provide a method as indicated which may beeasily and conveniently practiced economically with comparatively littledifficulty. An objective of the invention is, also, to provideapparatuses which can be easily and conveniently constructed at acomparatively nominal cost, which may be easily used, and which arecapable of giving prolonged, reliable performance with only moderate orminimal needs.

In accordance with the broad concepts of this invention these objectivesare achieved by supplying an electric current to a wire used in weldingas the wire is advanced by contacting a plurality of spaced pointsaround the outside or the periphery of the wire with wire engagingsurfaces located on electrically conductive rollers with sufficientpressure so as to cause the rollers to rotate in synchronism with thewire as the wire is advanced and so as to establish electrical contactwith the wire through the rollers. In practicing the present inventionin accordance with the concepts of the invention an apparatus utilizessuch rollers and means for supplying 'an electric current to them sothat the rollers may in turn supply the current to the wire as the wireis moved'or advanced.

BRIEF DESCRIPTION OF THE DRAWING A brief summary of this type isinherently incapable of setting forth the many aspects of an inventionsuch as the present invention embodying both method and apparatusconcepts. Further details of the invention and of these concepts will beapparent from a detailed consideration of this specification and of theaccompanying drawing in which:

FIG. 1 is a side-elevational view of one embodiment of a presentlypreferred apparatus in accordance with this invention in which part ofthe apparatus is broken away for explanatory purposes and in which theutilization of the apparatus is indicated in the diagrammatic manner;

FIG. 2 is a cross-sectional view of the apparatus shown in FIG. 1 takenat line 2-2 of FIG. 1;

FIG. 3 is a side-elevational view similar to FIG. 1 of a modified formof an apparatus in accordance with this invention which is preferred forsome types of utilization; and

FIG. 4 is a cross-sectional view taken at line 4-4 of FIG. 3.

It is to be emphasized that the concepts embodied within the specificstructures shown and utilized in the operation of these structures canbe embodied within other somewhat differently constructed and somewhatdifferently appearing apparatuses through the use or exercise of routineengineering skill. Thus, the present invention is not limited to thespecific structures shown or to the precise modes of operation of thesestructures. Instead, it is to be considered as embracing those conceptsand features defined in the appended claims regardless of how theseconcepts and features are utilized.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1 of thedrawing there is shown an apparatus utilized in transferring orsupplying current from a conventional power source 12 to a wire 14 sothat a weld utilizing metal from thewire 14 maybe created or laid downupon a metal member 16. It is to be understood that such a weld may becreated at the junction of several metal membersjf this is desired. Withthe apparatus 10 the power source 12 is electrically connected tothe'metal member '16 and to a housing 18 serving as a support memberwithin the apparatus 10.

This housing .18 is preferably manufactured from a carbon-bronzecomposition such as is commonly utilized for slip rings and other typesof electrical apparatuses so that it will easily conduct the currentsupplied to it. Such a material will carry a current of a comparativelyhigh density and also will serve so that rollers 20 and 22 positionedwithin parallel, cylindrical bores 24 or openings 24 in the housing 18will turn freely without undue friction impeding their movement.

These rollers 20 and 22 are preferably manufactured out of acomparatively hard refractory-like metal or metal alloy such as tungstenso that they will have a high current transfer capability and will serveto transfer current to the wire 14 without significant burning orpitting. These rollers 20 and 22 are dimensioned so as to fit closelywithin the bores 24 in such a manner that they can be rotated withinthese bores 24 so as to be in.

electrical contact with the housing 18 at all times.

In each of the bores 24 there is located a centrally positioned shaft26. These shafts 26 are each attached by a pin 28 to one of the rollers20. In the structure shown each of the other rollers 22 rotates freelyaroundone of the shafts 26. Small springs 30 biased between the surfaces32 of the rollers 22 remote from the rollers 20 and heads 34 on theshafts 26 serve to bias these rollers 22 towards the rollers 20. Thisbiasing action is employed so as to hold beveled engaging surfaces 36 onthe rollers 20 and 22 in such a manner that pressure is applied to fournearly equally spaced points around the periphery of the wire 14 as thiswire 14 passes through a hole 38 in the housing 18.

It will be noted that this hole 38 is located midway between the bores24 and intersects these bores 24. The hole 38 is also located so as toextend perpendicular to a plane passing through the axes of these bores24 and of the shafts 26. The hole 38 leads to a small guide tube ornozzle 40 attached to the housing 18 so as to extend therefrom towardsthe member 16. Preferably this tube 40 is formed of a non-conductivematerial such as a known ceramic which will convey and guide the wire 14with a minimum of friction. The housing 18 may be supported forutilization on any sort of a conventional support 42.

When the apparatus 10 is utilized in accordance with the method conceptsof this invention the wire 14 is continuously advanced towards thisapparatus 10 by a conventional wire feeder (not shown). If desired, itcan be advanced through conventional guide tubes serving to prevent itfrom buckling. As the wire 14 is moved in this manner current will besupplied from the power source 12 to the member 16 and to the housing 18so that a circuit is completed in a known pattern.

In completing the circuit the housing 18 will supply current to therollers 20 and 22 because of the contact with them. The contact of theserollers 20 and 22 with the wire 14 as this wire is moved will cause thewire 14 and the rollers 20 and 22 to move in synchronism with oneanother. This will be a consequence of the spring pressure exerted bythe springs 30 biasing the rollers 22 against the rollers 20. As theserollers 20 and 22 are held by the springs 30 so that the wire 14 isengaged by the engaging surfaces 36 current will, of course, betransferred through these rollers 20 and 22 to the wire 14.

It is to be noted that the rollers 20 and 22 in effect float" within thebores 24 so as to always adjust to a proper desired position relative tothe wire 14. The construction described is considered to be particularlydesirable in that it enables the apparatus 10 to accommodate wires ofdifferent diameters. When the beveled surfaces 36 are formed aspreferred at an angle of 30 to the axes of the rollers 20 and 22 a setof these rollers will satisfactorily adjust itself to a relatively widevariety of wire diameters. All of such wires of varying diameters arecapable of being held in an apparatus such as the apparatus 10 withadequate pressure for synchronous movement with the rollers 20 and 22without wire deformation or bending by appropriate adjustments or choiceof the springs 30 so that these springs 30 exert adequate pressure forelectrical contact and to cause synchronous movement without metaldeformation.

In FIG. 3 of the drawing there is shown a modified apparatus 50 which isclosely related to apparatuses as are disclosed in the Rygiol U.S. Pat.No. 3,396,888. Apparatuses as disclosed in this patent do not, however,have the utility of the apparatus 50. This apparatus 50 is designed tobe utilized in connection with a power source 52 corresponding to thepower source 12 in supplying a current toa wire 54 and to a metal member56 corresponding to the member 16 previously described. The apparatus 10differs from the apparatus 50 in that the apparatus 50 has the utilityof driving the wire 54 itself. Thus, this apparatus 50 can serve notonly to transfer a current to the wire 54, but also to feed the wire 54.

The apparatus 50 includes a housing 58 serving as a support memberwithin which there are fixed rollers 60 and floating rollers 62 mountedwithin four different cylindrical bores 64 in the housing 58. It will benoted that these bores 64 are located so that they are in parallelplanes which are spaced from one another in the housing 68. The rollers60 and 62 are carried by shafts 66 corresponding to the shafts 26 withthe fixed rollers 60 being secured to the shafts 66 by pins 68.Preferably these shafts 66 are formed of an electrically conductivematerial such as is specified in connection with the housing 18.

In the apparatus 50 springs 70 corresponding to the springs 30 arebiased between surfaces 72 on the floating rollers 62 and heads 74 onthe shafts 66 so as to bias the rollers 60 and 62 towards one another insuch a manner that beveled surfaces 76 corresponding to the surfaces 36engage the wire 54 as it passes through a hole 78 in the housing 68 to aguide tube 80 corresponding to the guide tube 40. It is to be noted thatthe hole 78 extends perpendicular to the planes in the bores 64 so as tointersect these bores 64. The housing 58 may be used on any convenientconventional support 82.

In the apparatus 50 the rollers 60 and 62 are rotatably carried withinthe bores 64 by conventional internal bearings 84. Further, the bores 64are connected by an enlarged internal cavity 86 designed to accommodateintegral gear flanges 88 on the rollers 60 and 62. These flanges 88carry gear teeth 90 which fit together so that each of the lowermostrollers 60 and 62 will rotate in synchronism with the roller 60 and 62located immediately above it.

The housing 58 also includes an internal interiorly enlarged bore 92within which a conventional drive shaft 94 is mounted in a conventionalmanner. This drive shaft 94 is secured to two separate drive gears 96,one of which is in internal contact with each of the two lowermost fixedrollers 60 and the other of which is in internal contact with each ofthe two lowermost floating rollers 62. This structure is designed sothat as the shaft 94 is turned the rollers 60 and 62 will be turned insynchronism with it so as to advance the wire 54 as this wire is heldbetween the beveled surfaces 76 as indicated in connection with thisapparatus through the operation of the spring 70.

In the apparatus 50 the shafts 66 are formed of an electricallyconductive material so that current can be conveyed to them from apressure or transfer plate 98 as shown in FIG. 4 of the drawing. Thisplate 98 is preferably formed of a material such as was noted inconnection with the housing 18 with small bosses 100 on it will bearagainst the ends of the shafts 66 in order to establish electricalcontact with them. This plate 98 is preferably resiliently held inposition in a cavity 102 in the housing 58 by means of a small biasingsprings 104. It will be noted that the power source 52 is directlyconnected to this plate 98.

With the described structure as the shaft 94 is turned not only will thewire 54 be advanced, but current will be transferred from the plate 98to the shafts 66 and thence to the rollers 60 and 62. For there to besuch transfer between the rollers 60 and 62 and the shafts 66 theserollers 60 and 62 must fit closely with respect to these shafts. Theserollers 60 and 62 will then transfer the current to the wire 54 as thewire is advanced so that simultaneously the wire 54 is both electrifiedand the mechanical structure described for rotating the various rollers60 and 62.

The apparatuses l0 and 50 indicated are comparatively simple, effectiveapparatuses which can be constructed at relative nominal costs. Theseapparatuses l0 and 50 are comparatively simple to utilize. Dependingupon the nature of the wire being used in a welding operation and theavailability of other supporting equipment such as a known wire feeder,in some applications it may be desirable to utilize an apparatus such asthe apparatus 10 while in other applications it may be desirable toutilize an apparatus such as the apparatus 50. An important feature ofthese apparatuses 10 and 50 lies in the fact that the constructiondescribed permits these apparatuses to be used with and to adjust towires of various diameters. In any utilization of an apparatus asdescribed such an apparatus will normally give reliable performance overan extended period and will only require moderate attention.

One of the major reasons as to the latter being true pertains to themanner in which current is transferred in apparatuses as described. Inthese apparatuses the rollers indicated engage a wire at four differentpoints around the periphery of the wires which are in a plane transverseto the center of the wire. Because of this the amount of current flowingto the wire will be divided amongst the four different rollers so as toreduce the current flow at any one point to one-fourth of the totalcurrent being transferred.

This is to be compared with the manner in which contact tubes and inparticular worn contact tubes operate. In such tubes frequently theentire current flow through the wire is concentrated to one area wherethe wire bends to make engagement with the tube interior. Such aconcentration of current is known to cause socalled burn outs which ineffect may be considered as a type of weld securing the wire to thecontact tube so that the wire will not beadvanced in a desired manner.

This type of consequence is avoided with the present invention becauseof the current distribution and because of the manner in which thecurrent is transferred. Such transfer occurs by rolling contact alonglines eminenting from the points where the rollers engage a wire. Withrollers as described there is little or no danger of arcing securing thewire to the rollers. Further, the contact between the rollers and thewire is far enough from the axes of rotation of the rollers so that whatmay be considered as a lever arm-type of advantage is achieved whichtends to prevent adherence between the wire and the rollers such asoccurs in conventional contact tubes.

I claim:

1. An apparatus for use in supplying an electric current to a wire assuch a wire 'is advanced to a welding surface where an electric weld iscreated through the utilization of the wire and the current supplied tothe wire, in which the improvement comprises:

a support member,

two pairs of rollers of a refractory metal or alloy thereof, each ofsaid rollers being electrically conductive, each of said rollers havinga beveled wire engaging surface,

two parallel axles, the rollers of each of said pairs being located onone of said axles so that said wire engaging surfaces are capable ofengaging a wire positioned so as to extend relative to them and saidsupport member at a plurality of points a first roller of each of saidpairs being positioned upon the axle upon which it is located so as tobe incapable of moving along its axis relative to the axle upon which itis located, said first rollers of said pairs being located adjacent toone another,

the other, second roller, of each of said pairs being rotatably heldupon the axles upon which they are located so as to be capable of beingmoved axially along the length of the axles upon which they are located,

spring means for independently moving each of said second rollerstowards its associated first roller, said spring means serving to biassaid rollers of said pairs so that such a wire is engaged firmly enoughso that all of said rollers rotate in synchronism with such a wire asthe wire is advanced and firmly enough so as to establish electricalcontact with such a wire,

means for supplying an electric current to said rollers as said rollersrotate so that said rollers may in turn supply the current supplied tothem to a wire passing between them so that such current may be used inmaking a weld through the utilization of the wire and the current.

2. An apparatus as claimed in claim 1 wherein:

said rollers are rotated by movement of said wire.

3. An apparatus as claimed in claim 1 including:

means for rotating said rollers in synchronism with one another, theengagement of said rollers serving to cause advancement of said wire.

4. An apparatus as claimed in claim 1 wherein:

there are two hollow bores within said support member,

said axles are unattached to said support member,

said rollers are rotatably mounted on said support members by beingpositioned within said bores, and

said rollers fit closely within said bores so as to be in electricalcontact with said support members through the walls of said bores, and

said means for supplying is connected to said support member so as tosupply current to said support member.

5. An apparatus as claimed in claim 1 including:

mechanical means for rotating all of said rollers in synchronism withone another and wherein, said means for supplying includes rotarycontact means engaging said mechanical means.

1. An apparatus for use in supplying an electric current to a wire assuch a wire is advanced to a welding surface where an electric weld iscreated through the utilization of the wire and the current supplied tothe wire, in which the improvement comprises: a support member, twopairs of rollers of a refractory metal or alloy thereof, each of saidrollers being electrically conductive, each of said rollers having abeveled wire engaging surface, two parallel axles, the rollers of eachof said pairs being located on one of said axles so that said wireengaging surfaces are capable of engaging a wire positioned so as toextend relative to them and said support member at a plurality of pointsa first roller of each of said pairs being positioned upon the axle uponwhich it is located so as to be incapable of moving along its axisrelative to the axle upon which it is located, said first rollers ofsaid pairs being located adjacent to one another, the other, secondroller, of each of said pairs being rotatably held upon the axles uponwhich they are located so as to be capable of being moved axially alongthe length of the axles upon which they are located, spring means forindependently moving each of said second rollers towards its associatedfirst roller, said spring means serving to bias said rollers of saidpairs so that such a wire is engaged firmly enough so that all of saidrollers rotate in synchronism with such a wire as the wire is advancedand firmly enough so as to establish electrical contact with such awire, means for supplying an electric current to said rollers as saidrollers rotate so that said rollers may in turn supply the currentsupplied to them to a wire passing between them so that such current maybe used in making a weld through the utilization of the wire and thecurrent.
 2. An apparatus as claimed in claim 1 wherein: said rollers arerotated by movement of said wire.
 3. An apparatus as claimed in claim 1including: means for rotating said rollers in synchronism with oneanother, the engagement of said rollers serving to cause advancement ofsaid wire.
 4. An apparatus as claimed in claim 1 wherein: there are twohollow bores within said support member, said axles are unattached tosaid support member, said rollers are rotatably mounted on said supportmembers by being positioned within said bores, and said rollers fitclosely within said bores so as to be in electrical contact with saidsupport members through the walls of said bores, and said means forsupplying is connected to said support member so as to supply current tosaid support member.
 5. An apparatus as claimed in claim 1 including:mechanical means for rotating all of said rollers in synchronism withone another and wherein, said means for supplying includes rotarycontact means engaging said mechanical means.